FIG. 1 refers to application in mining and illustrates a simplified open-pit mine 100. The mine 100 comprises an ore deposit 102, two blasthole drills 104 and 105, a shovel 106, empty trucks 108 and 110 and loaded trucks 112, 114 and 116. The mine 100 further comprises a supply machine 118, such as a fuel truck. The drill 104 drills blastholes, the material is blasted and then loaded onto truck 110. The truck 110 then transports the material to a processing plant 118. Similarly, drill 105 also drills blastholes for later blasting.
While some of the examples herein relate to the mining of iron ore, it is to be understood that the invention is also applicable to other mining and non-mining operations, such as extraction of coal, copper or gold or monitoring of deformations of natural or man-made slopes, excavations, constructions and mobile plants.
Mine 100 further comprises a control centre 122 connected to an antenna 124 and hosting on a computer 126 a mine control system. The mine control system 126 monitors operation and status data received from the mining machines wirelessly via antenna 124. In one example, the control centre 122 is located in proximity to the mine site while in other examples, the control centre 122 is remote from the mine site, such as in the closest major city or in the headquarters of the resource company.
As a result of in situ stresses in the rock mass, sub-optimal mine design given the uncertain geological conditions, continuous blasting and extraction of material from mine 100 or a combination of the above, some areas of mine 100 may become unstable. For example, an area 130 is highlighted in FIG. 1, which may become unstable. Unstable areas, and in particular, unstable walls, such as slopes, can fail and collapse, which poses a significant risk to the live of staff as well as to the commercial operation of the mine.
There exist monitoring systems that monitor potentially unstable areas, such as systems using laser range finders and radars. These existing systems generally monitor the line of sight movement. That is, these existing systems monitor whether the potentially unstable area moves towards or away from the laser and/or radar. A significant acceleration can indicate that the area is unstable and the system can raise an alarm. In many cases, however, the prediction of instability is inaccurate and in particular, areas have become unstable where the line of sight movement and/or acceleration did not indicate any problems.
US 2004/0046690 discloses a phase map calculated from radar images and video data to serve as a visual history of faults. While this offers a visual aid to the operator for monitoring line of sight movements, the outcome suffers from the above problem of insufficient inaccuracy especially when used for automatic monitoring without relying on a human operator.
U.S. Pat. No. 8,154,435 Pett discloses using a 2D interferometric synthetic aperture radar (InSAR) technique that provides a third resolving dimension. In particular, the third dimension is resolved by using a multi-baseline differential InSAR approach from two separate phase centres. While this solution is not limited to line of sight movement, it relies on multiple radar locations, which increases installation cost and complexity. Further, radar measurements have poor spatial resolution, which again leads to inaccurate results.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.